GARDEN CITY, N.Y. -- Federal, state and local law enforcement agents raided dozens of businesses around Long Island on Tuesday and arrested people on money laundering and immigration charges.

Arrest warrants were unsealed against 11 defendants. Seven were charged with laundering as much as $28 million in proceeds from dozens of gas stations and mini-markets over several years. Four others were cited on immigration charges: One man was accused of re-entering the United States after being deported, while three others were charged with marriage fraud.

"They are all part of the same organization," said Martin Ficke, special agent in charge for the U.S. Immigration and Customs Enforcement bureau.

He said the investigation was still in the early stages and more arrests were likely.

During the raids, part of a crackdown called Operation Ankara, immigration officials also took into custody 57 suspected undocumented aliens. There were suspicions that the aliens were smuggled into the United States and forced to work for the operators of the gas stations as repayment for entry into the country, Ficke said.

The raids, which involved an estimated 200 law enforcement agents, also yielded massive amounts of documents and business records linked to the operation.

The suspects were arraigned on various charges at U.S. District Court in Central Islip. Five of the seven defendants in the money laundering case were ordered held until a bail hearing on Thursday; the remaining two have yet to be arrested.

Two of the four immigration violation defendants have been taken into custody; one was ordered held until a bail hearing Thursday and the other was released on a $50,000 personal recognizance bond, said Joseph Conway, the assistant U.S. attorney in the Central Islip office.

The investigation was named Operation Ankara, after the capital of Turkey, because most of the suspects are believed to be Turkish nationals. Conway said the arrests were not related to terrorism.

The money laundering charges are tied to a scheme called "structuring," said Joseph Foy, a spokesman for the Internal Revenue Service. The suspects made bank deposits of less than $10,000 to evade federal currency reporting requirements, prosecutors said.